Conventionally, a vehicle engine includes: a cylinder head; a cam housing fixed to a top of a cylinder head; a cam cap fixed to a top of the cam housing; a camshaft rotatably supported between the cam housing and the cam cap; a cam provided around the camshaft; a rocker arm configured to be pushed by the cam; and a lash adjuster that supports one end of the rocker arm from below. One of such vehicle engines includes a cam housing having a mounting recess, wherein the lash adjuster is mounted.
In such a vehicle engine, when the cam pushes the rocker arm, the pressure of the cam is exerted sequentially on the rocker arm, the lash adjuster, and the cam housing.
Therefore, the cam housing of the conventional vehicle engine needs to have a higher rigidity so as not to deform under the pressure of the cam.
In order to provide the higher rigidity of the cam housing, thickening the cam housing is necessary. However, thickening the cam housing can result in upsizing and weight increase of the cam housing. Accordingly, the space on the top of the cylinder head for fixing such a cam housing can be insufficient.
Thus, there is a need for a vehicle engine that exerts less pressure of the cam on the cam housing so as to permit downsizing of the cam housing.